I run those exact spacers, which I also purchased from EE, and have been very happy with them. While it is impossible to be exact, I think one will provide a little less than 1/2 inch of lift, two will provice a little less than one inch of lift.
I am running just one, on the top of my rear springs. Remember that this one is only for the rear spring, there is a different version for the front spring.
I would strongly recommend using these. Not just because it provides a little extra height, but more importantantly it will greatly smooth out the ride of your vehicle by absorbing road shock. This is the exact reason the spacer was created in the first place for the Range Rovers.
I would attach a photo of the matching front spacer, but it is easier to just go to EE's website, which has much better photos.